1. Field of the Invention
The present invention relates to a method for dehalogenating aromatic compounds, and specifically to a method for selective dehalogenation of condensed polyaromatic, halogenated compounds via reduction reactions in the presence of carbon-based catalysts.
2. Background of the Invention
The recognition of the toxicity and carcinogenic properties of halogenated compounds has led to restrictions on the utilization and disposal of such materials. Condensed polyaromatic compounds, such as 1-chloronaphthalene, have industrial applications as solvents, dyes, flame-retardants, and have also been involved in the manufacture of instrument seals and insecticides. Polychlorinated biphenyls (PCBs) are related materials which have had much publicity due to their persistence and adverse impacts on the environment.
The destruction of these materials has proved costly. Presently, incineration is considered the destruction method of choice, with temperatures of 1000.degree. C. required for adequate detoxification.
As a more economical alternative, catalysts have been employed to convert, under milder conditions, the halogenated compounds to relatively innocuous materials, such as carbon dioxide, water and halogen salts and other halogen-containing inorganic compounds such as acid. However, a disadvantage to this method is the loss of carbon as carbon dioxide, especially if the toxic material is present in a mixture with nontoxic materials that also would be destroyed in the process.
A need exists in the art to detoxify halogenated compounds, both neat and in mixtures, while yielding, as products of the reaction, the corresponding unhalogenated compounds. In this way, the detoxified materials can be reutilized.